Absorption refrigerating apparatus



Nov. 7, 1939. c. c. COONS ABSORPTION REFRIGERATING APPARATUS 'Filed Aug.8, 1936 9 on the interior Patented Nov. 7, 1939 Application August 8,

This invention PATENT OFFICE 13 Claims.

relates to continuous absorption refrigerating apparatus using inert gasand more particularly means for regulating the pressure therein.

It is desirable to have installed in an absorption refrigerating systemusing inert gas, means to increase automatically the total pressure inthe system as the room temperature increases and to decrease the totalpressure automatically as the room temperature decreases. peratures, thecondensation of ant entering the condenser at lower room the systemdiminished by some the system will operate with a perature thusdecreasing the and otherwise improving the system.

It is an object of the present vide pressure regulating means tomaticand which ing the desired pressure in a tem using inert gas.

It is another object of novel means for regulating the frigeratingsystem.

Other objects and advantages of the arrangement and construcnovelfeatures tion of parts as will be apparent temperatures with the At highroom temgaseous refrigeris thus assured, and

pressure of regulating means, lower boiler temrate of corrosionoperation of the invention to prowhich will be auwill be reliable inmaintainrefrigerating systhe invention to provide pressure in a reresidein certain from the following description taken in connection with theaccompanying drawing in which Figure 1 is a diagrammatic a continuousabsorption ing inert gas and in which the is incorporated, the pressureshown in cross section.

r Figure 2 is an enlarged view of a portion of the the arrangement ofpressure chamber used in representation of refrigerating systemuspresent invention chamber being Figure l and showing the bellowsconstruction thereof, the view being taken on the line 2-2 of Figure land Figure 3 is a transverse cross-sectional view of the pressurechamber,

the line 3-3 thereof.

Referring to seen that a continuous absorp the drawing in the view beingtaken on detail, it will be tion refrigerating J these parts beingconnected by various conduits to form the completed refrigerationsystem.

A conventional gas lift pump ll may be employed to lift absorptionliquid from the boiler into the gas separation erant developed in theboiler through the conduit l2 into chamber and the refrigsystem may flowthe condenser C where it is liquefied and flows into the evaporator Ethrough the conduit [3.

Inert gas is circulated between the absorber and the evaporator by meansof the inert gas ABSORPTION REFRIGERATING APPARATUS Curtis 0. Coons,North Canton,

to The Hoover Company,

a corporation of Ohio Ohio, assignor North Canton, Ohio,

1936, Serial No. 94,946

absorber by means of the ab-.

from the bottom of the absorber back to the boiler through the conduit20.

The system may be charged with ammonia, water and nitrogen asrefrigerant, absorption liquid and inert gas in accordance with knownpractice.

In accordance with the present invention, a pressure chamber 2| isconnected to some part of the system, as for example the bottom of theabsorber, by means of the conduit 22. The pressure chamber 2| is merelya closed vessel and has an expansible chamber or bellows construction 23therein. Any other suitable collapsible device may be substituted forthe bellows 23, as for example, a rubber cylinder.

In the arrangement shown, the bellows 23 is welded to the top of thecylinder 2| and a valve 24 is connected to the top of the cylinder sothat fluid may be charged into the expansible bellows chamberindependently of the charge to the refrigerating apparatus in general.

From experiment, it has been estimated that in a 60 degree Fahrenheitroom, an absorption refrigerating system using a refrigerant, anabsorbent and an inert gas of the usual construction with the absorberand condenser air-cooled, the system will operate satisfactorily withthe internal pressure about 200 pounds per square inch. On the otherhand, in a 100 degree Fahrenheitroom the same system should have apressure of about 3'70 pounds per square inch to operate satisfactorily.Without a pressure regulator, the internal pressure would not increasesufficiently under normal conditions if the room temperature changedfrom 60 degrees Fahrenheit to 100 degrees Fahrenheit for the internalpressure of this system would be increased only up to about 250 poundsper square inch.

In accordance with the present invention, the desired pressure changemay be brought about within the system, however. The pressure chamber 2|andbellows 23 function to increase internal pressure in the refrigeratorwith an increase in room temperature by the expansion of the bellows 23as the result of the expansion of the fluids therein. In order for thissystem to operate, the fluids within the bellows 23 must expand with anincrease in room temperature and create a higher pressure than theexpansion of the fluids in the refrigerating system itself creates. Asthe bellows 23 expands, it compresses the gases in the cylinder 2| andforces them into the refrigerating apparatus, thus increasing the totalpressure in the refrigerating system.

The bellows is caused to expand with an increase in room temperature byan increase in pressure within the bellows due to the heating of thefluid or fluids contained therein.

It will be apparent, therefore, that for any desired pressure increasein the internal pressure of the refrigerator for a given increase inroom temperature, it is only necessary to select a system of fluids tobe charged into the bellows 23 that will yield the desired pressure atany desired room temperature. The fluids selected for charging into thebellows 23 must, of course, be non-corrosive with respect thereto.

For an air-cooled, ammonia absorption refrigerator using water asabsorbent and nitrogen as inert gas-it may be desirable to increaseinternal pressure from about 200 pounds to 370 pounds per square inchwith an increase in room temperature from 60 to 100 degrees Fahrenheitas in the example given above. In this system, liquid ammonia and liquidpropane are proposed in ac cordance with the present invention for'usein the bellows 23.- Since these two fluids are practically immiscible,each will exert its own vapor pressure independently of the other. As aconsequence the system within the bellows 23 will have a pressure ofabout 210 pounds at a temperature of 60 degrees Fahrenheit and may havepounds at a temperature of 100 degrees Fahrenheit.

The bellows 23 must be so proportioned with respect to the volume of thecylinder that the correct relation to the volume of the refrigeratingapparatus is maintained. The volume of the cylinder and the bellows mustbe made sufliciently large in relation to the volume of that part of therefrigerator into which the gas is compressed that the pressure in therefrigerator will be equivalent to the pressure in the bellows or atleast approximately equivalent at all temperatures. It is roughlyestimated that if the gas part of the refrigerator such as the absorber,evaporator and inert gas conduits had a volume of four liters, thebellows must be able to expand into a volume of three liters to producea pressure increase from 210 to 3'70 pounds per square inch.

If the pressure vessel were installed above the absorber, thetemperature of the pressure vessel would always be above the roomtemperature because it would receive heat from the absorber. Theabsorber temperature during normal operation is 20 to 25 the roomtemperature. If the pressure vessel is so installed the temperature ofthe pressure vessel could be made to vary from 80 degrees Fahrenheit to120 degrees Fahrenheit with an increase in room temperature from 60 to100 degrees Fahrenheit. Under these conditions liquid ammonia alonecould be charged into the bellows and would give a sufflcient pressureto expand the bellows for at 120 degrees Fahrenheit the vapor pressureof ammonia is 290 pounds.

It will be apparent, therefore, that almost any desired pressureincrease within the bellows could the bellows by the use of such systemsor combinations as ammonia and propane, ammonia alone, ammonia andwater, ammonia propane and water, and ammonia and some inert gas such asnitrogen and hydrogen.

degrees Fahrenheit higher than- The instant invention produces severaldesired functions within the system with results greatly improved overthose previously produced by similar apparatus. In previous deviceswhich were designed for the purpose of regulating the threefluidabsorption refrigerating system in response to changes in atmospherictemperature conditions, the pressure in the apparatus was raised byincreasing the quantity of inert gas in the active portions of thesystem and by trapping out of the active portions of the system a volumeof substantially pure refrigerant vapor equal to the original volume ofinert gas added to the active circuit and existing at the higherpressure. Such apparatus produces the desired result of increasingsystem pressure but it also greatly impairs the efliciency of theincrease the pressure of the system and will ma- I terially increase thequantity of inert gas circulating through the active portions of thesystem, but it will not materially change the quantity of refrigerantcontained in the solution or the quantity circulating through the'activeportions of the system.

When the pressure of the apparatus increases, the quantity of ammoniavapor present in the the apparatus. The quantity of refrigerant which isadded to the condenser is not great because of the relatively smallvolume of the condenser tubes which have In summation, therefore, it maybe said that a rise in temperature produces the following changes in thesystem. The quantity of inert gas in the active circuits is materiallyincreased. The quantity of refrigerant circulating through the activeportions of the circuit is slightly increased. The quantity ofrefrigerant contained in solution may be slightly increased or decreaseddepending entirely upon the proportions of the condenser and thepressure vessel, but in any event no material change is produced in thesolution concentration. Moreover, due to the greater quantity of inertgas provided at higher pressure, the concentration'of refrigerant vaporin the inert gas circuit tends to decrease in the well known manner inorder to permit eflicient It will be apparent, therefore, that whileonly one embodiment of the invention is shown and described herein.various changes may be made in the arrangement and construction of partswithout departing from the spirit of the invention or the scope of theannexed claims.

I claim:

1. The combination with a continuous absorption refrigerating systemusing an inert gas of means for regulating the pressure therein inaccordance with temperature conditions, said means including a pressurevessel connected to a part of said system and an expansible element inthe pressure vessel for varying the volume therein in response totemperature conditions.

2. The combination with a continuous absorption refrigerating systemusing an inert gas of means for regulating the pressure therein inaccordance with temperature conditions, said means including a pressurevessel connected to a part of said system and an expansible element inthe pressure vessel for varying the volume therein in response totemperature conditions, said expansible element consisting of a bellowschamber filled with an expansible fluid.

3. The combination with a continuous absorption refrigerating systemusing an inert gas of means for regulating the pressure therein inaccordance with temperature conditions, said means including a pressurevessel connected to a part of said system and an expansible element inthe pressure vessel for varying the volume therein in response totemperature conditions, said expansible element having ammonia andpropane therein.

4. The combination with a continuous absorption refrigerating systemusing an inert gas of means for regulating the pressure therein inaccordance with temperature conditions, said means including a pressurevessel connected to a part of said system and an expansible element inthe pressure vessel for ,varying the volume therein in response totemperature conditions, said expansion chamber having fluids thereinwhich cause the pressure therein to increase a greater amount per degreeincrease in temperature than the normal increase in pressure in therefrigerating system per degree increase in temperature.

5. The combination with an air-cooled absorber of a continuousabsorption refrigerating system using inert gas of a pressure vesselconnected thereto, said pressure vessel havingan expansible elementassociated therewith and adapted to change the effective volume of thepressure vessel as the temperature of operation of the absorber varies.

6. The combination with a continuous absorption refrigeration systemusing inert gas of means for regulating the operation of the system inaccordance with temperature conditions comprising a device for varyingthe effective volume of the system.

'7. The method of regulating the internal conditions of an air cooledcontinuous absorption refrigerating system using inert gas whichincludes the step of increasing or decreasing the volume of such asystem in response to temperature changes.

8. That improvement in the art of continuous absorption refrigerationusing inert gas which comprises automatically varying the quantity ofinert gas contained in an inactive portion of the system in response toexternal temperature conditions, without materially altering thequantity of refrigerant contained in the active portion of the system.

9. That improvement in the art of refrigeration which includes the stepsof evaporating a refrigerant into an inert gas in an evaporating zone toproduce refrigeration, removing the refrigerant vapor from the inert gasin an absorbing zone by contacting the mixture with an absorbent for therefrigerant, rejecting the heat of absorption to cooling air, and addingor subtracting inert gas to said absorbing zone in response to changesin the temperature of the cooling air without materially altering theconcentration of the refrigerant in the absorbent.

10. Absorption refrigerating apparatus comprising a solution circuitincluding a boiler and an absorber, a pressure equalizing medium circuitincluding an evaporator and said absorber means for supplyingrefrigerant generated in said boiler to said evaporator in liquid phase,means included in said pressure equalizing medium circuit adapted topropel pressure equalizing medium therethrough, and means for alteringthe volume of said pressure equalizing medium circuit withoutsubstantially altering the volume of said solution circuit.

11. That improvement in the art of refrigeration which includes thesteps of expelling refrigerant from a generating zone, circulating asubstantially constant quantity of absorption solution through a circuitincluding the generating zone and an absorbing zone, circulating apressure equalizing medium through a circuit including an evaporatingzone and the absorbing zone, circulating a substantially constantquantity of refrigerant through a circuit including all of said zonesand a heat rejecting zone, and varying the quantity of pressureequalizing medium circulating through the evaporating and absorbingzones in response to changes in atmospheric temperature conditions.

12. That improvement in the art of refrigeration involving a systemhaving a plurality of active zones through which various fluidscirculate which includes the steps of circulating a pressure equalizingmedium through a circuit including evaporating and absorbing zones,circulating absorbing solution through a circuit including generatingand absorbing zones, liquefying vapor expelled in the generating zone byheat exchange with a cooling medium, conveying the liquid refrigerant tothe evaporating zone, altering the concentration of one of said fluidsin response to changes in the temperature of maintaining the quantity ofrefrigerant in the active zones of the system substantially constant.

13. Refrigerating apparatus comprising a pressure equalizing mediumcircuit including an evaporator and an absorber, a solution circuitincluding a generator and said absorber, means for supplying refrigerantvaporized in said generator to said evaporator in liquid phase, andmeans for withdrawing pressure equalizing medium from said pressureequalizing medium circuit and for adding pressure equalizing medium tosaid pressure equalizing medium circuit in accordance with externaltemperature conditions, said last mentioned means beingconstructed andarranged to withdraw or add pressure equalizing medium withoutsubstantially aifecting the quantities of other fluids circulating inthe apparatus.

cua'rrs c. COONS.

the cooling medium, and

